新型扁锥腔红外CO2气体传感器系统研究

为提高红外CO2气体传感器测量精度，本文利用非分光红外探测技术设计了以白炽灯红外光源、双通道热电堆红外探测器和扁锥腔体为主要元件构成的新型红外CO2气体传感器。采用Zemax光路仿真分析，研究了新型扁锥腔CO2气体传感器探测面光强分布，并结合ANSYS FLUENT软件对扁锥型气室进行结构优化。以STM32单片机为核心，实现了光源电调制，采用ICL7650放大处理探测器的电信号，再由STM32控制ADC进行信号采集，提高了测量系统的抗干扰能力。在此基础上开展了标定和测试实验，结果表明：在25℃环境中，传感器能够准确检测出0-2000 ppm量程范围内的CO2气体浓度，具有较好的重复性和长期稳定性。三组实验平均相对误差最大为5.2%，重复性误差最大为5.5%，稳定度为2.3%。该研究对红外CO2气体传感器结构优化和测量精度的提高具有参考意义。

Research on Novel Flat Cone Cavity Infrared CO2 Gas Sensor System

In order to improve the measurement accuracy of infrared CO2 gas sensors, a novel infrared CO2 gas sensor is designed by non-spectral infrared detection technology. It chooses incandescent infrared light source, dual-channel thermopile detector and flat cone cavity as the main components. The distribution of light intensity on the detection surface of the novel CO2 gas sensor was studied by using Zemax software, and the structure of the flat-cone gas cell was optimized by ANSYS FLUENT software. The STM32 singlechip is applied as the core component to achieve the electrical modulation of the light source, and the ICL7650 is used to amplify the electrical signal output from the detector, and then STM32 controls the ADC to perform signal acquisition. This circuit can effectively improve the signal to noise ratio of the system. On?the?base?of?these, the calibration and test experiments were carried out, and the results showed that in the concentration range of 0-2000 ppm, CO2 concentration can be accurately detected by the gas sensor at 25 °C, and the measurement results have good repeatability and long-term stability. The average relative error of the three groups of experiments was less than 5.2%, the maximum repeatability error was 5.5%, and the stability was 2.3%, respectively. In a word, this study presents a reference for the structural optimization of the infrared CO2 gas sensor and the improvement of the measurement accuracy.